CENTRAL WORKSHOP, U.I.E.T.
CHHATRAPATI SHAHU JI MAHARAJ UNIVERSITY, KANPUR
INSTRUCTION ON MANUALS
WORKSHOP PRACTICE TCA 102
(MOULDING SHOP)
INTRODUCTION
Sand is the principle basic moulding material used by the foundry
man whether. It is for iron steel Non-ferrous or light alloy casting.
Original natural day mixed with the grain of silica sand. These
silica and are known by the terms sea – sand, river sand etc. The
best term is “silica sand”. The green of silica sand are very
refractory. They can be heated to a high temperature before their
surfaces begin to mill and cause the grains to stick together, but
the impurities found with some of them such as Mica, Felspars
and Alkaline.
The principle characteristics of the process the production of casting with a high
standard of surface finish and dimensional accuracy a high rate of production
from a small floor space and a mark reduction in the amount of material such as
sand and box parts.
FERROUS METALS – Those metal which contain iron as a chief constitute
called ferrous metals .
Example – Pig iron, Cost iron, Mild steel, Wrought iron, Stainless steel etc.
NON – FERROUS METALS - Those metal which contain other metal to
leave iron as a chief constitute called non- ferrous metals.
Example – Copper, Aluminium, Zinc, Lead, Tin etc
ALLOY METALS – when two or three metals melt together then the
resulting metal called Alloy metals.
TYPE OF SAND USED FOR DIFFERENT TYPE OF COSTING
AND METALS
While the chemical composition of sand gives a valuable guide to its refractory
character the primary factors in determining the working properties of sand are
following.
1.
2.
3.
Shape, size distribution and surface character of the grain.
The amount and type of clay.
The moisture contend porosity or permeability.
The permeability of the mass on the flow ability and deformation value of sand.
1.
For steel casting is used 93% Silica sand, 3.5% Bentonite, 0.5% Dextrin 3%
water.
2.
Green Sand – Sand is green or undried condition casting into green sand
undried mould is common practice for majority of small and medium size
ferrous and non ferrous casting.
DRY SAND – This term indicates that moulding sand which was orginally having
excess moisture content but the same has been evaporated from it by drying its
mould in a suitable oven.
FACING SAND – It is also known as fat sand. These terms are used for that sand
which forms the face of the mould, i.e., rammed around the pattern surface. It is
nothing but the fresh prepared and well tempered foundry sand. Initial coating
around the pattern surface is given by this sand and the remainder of the flask is
filled with floor sand to effect economy.
PARTING SAND – This term denotes that sand which is sprinkled on the pattern
and the parting surfaces of the mould so that the sand mass of one flask does not
stick to that of the other or to the pattern. The ‘burnt’ sand and dry silica sand are
used for this purpose.
CORE SAND – The sand which carries a high silica content and is used for
making cores is known as core sand.
OIL SAND – Silica sand using oil binders is known as oil sand.
MOLASSES SAND – This term denotes the denotes the sand which carries
molasses as binder. It is very useful for making moulds of small castings having
intricate shapes and thin sections. Also it is used as core sand.
MOULDIING TOOLS
1. Moulding box or Flask
2. Cleaner
3. Heart Trowels
4. Heart and Square Trowels
5. Brush
7. Round rammer
9. Riddle (Square)
6. Pin rammer
8. Small rammer
10. Riddle (Round)
11. Runner sprue
12. Sprit level
13. Vent wire
14. Showel
15. Swab
16. Spade
17. Clamp
19. Hent bellows
18. Wooden smoother
Melting Tools a. Crucible – for melting the metal in the crucible ferrous and non- ferrous
metals.
b. Crucible Tong – It is used for lifting the crucible from pit furnace.
c. Crucible career – It is used for carried the crucible and pouring the metal in
mould.
d. Rocking rod – Titening the hard cake in the fit ferness by rocking rod.
Fitting of the casting
Or
Cleaning of the casting
Hand tools are used :-
1. Hammer
2. Chisel
3. Hacksaw
4. Wire Brush
Machines are used
1.
Tumbling - In this method the castings to be cleaned are placed inside large
steel barrels, together with a number of small cast iron pieces called stars.
Both ends of the barrel are closed and the same rotated along a horizontal or
inclined axis for about half an hour or so. The casting during this period of
rotation, rub against each other and the stars to obtain a clean surface, free of
sand and scale. It is very efficient method of cleaning and further
requirements of grinding etc. Are minimised considerably.
2.
Shot blasting – This method is similar to sand blasting, but here Metallic
Abrasives are fed into the air blast instead of the sand grains. They may
either be in the form of shots or cut-wires. The common materials used as
abrasives are malleable iron, cast steel and chilled iron. The main advantage
of this process is that it provides a very fast rate of cleaning.
c. Hydroblasting – In this process a high velocity stream consisting of water sand is
thrown on to the casting surface with a speed of about 6000 meters per minute, to
strike the surface at an inclination of about 450 with it. This is also very effective
method.
FURNACES
a.
BLAST FURNACE – It is for melting the iron ore. The output as pig iron
and steel with different process.
Input – Iron
Output – Pig iron
Fuel – Hard coke
b. Fit Furnace – It is only for ferrous and non – ferrous metals.
Fuel – Hard coke
c. Oil Fired Tilling Furnace – It is for ferrous and non – ferrous metals.
Fuel – Disel and Air
d. Cupola Furnace – It is only for pig iron and cast iron.
Input – Pig iron
Out put – Cast iron
Fuel – Hard coke
e. Electric are direct and Indirect Furnace – This furnace is used for steel casting
Melting Points of Metals
Pig iron or cast iron
1093 0 C - 1300 0 C
Steel
1563 0 C
Copper
1010 0 C – 10850 C
Aluminium
6600 C – 704 0 C
Zinc
419 0 C
Lead
322 0 C – 327 0 C
Tin
232 0 C – 267 0 C
Patterns :- A pattern may be defined as a Replica or Fascimile Model of the
desired casting which, when packed or embedded in a suitable moulding
material, produces a cavity called Mould.
This cavity, when filled with molten metal, produces the desired casting after
solidification of the poured metal. It is direct duplication, the pattern very
closely conforms to the shape and size of the desired casting, except for a few
variations due to the necessary allowances.
Types of Patterns
a. Solid Pattern -
b. Split Pattern
c. Gated Pattern
d. Match Plate Pattern
e. Pattern with Loose - Pieces
f. Skeleton Pattern
g. Sweep Pattern
METAL PATTERN IS USED FOR MASS PRODUCTION
ALLUMINIUM VERY SOFT CHEAP AND LIGHT
Core and Core Making - A core box should be made which be made which
produce a core corresponding to the two prints on the pattern and circular hollow
section of the casting the core each half core box is then filled with molasses
sand and should be rammed and evenly.
A rein forcing wire may be placed in the core. The two holes of the box are then
closed together. Locating dowels ensuring correct matching. The open ends of
the core are finished off. By ramming tucking and making firm. The sand thus
rammed into the core box becomes comes compact mass of the require shape.
This sand shape or core must no be with drawn form the core box and so treated
that it can be handled place in the mould and fulfil its function in providing a
hollow casting.
The treatment of the core depends on the nature and types of sand used. The
majority of sand require that the core be dried or baked at a temperature of 520
of for a period of time 1 ½ hours to four according to the size.
Type of Allowances
1.
2.
3.
4.
5.
Shrinkage Allowance
Machining Allowance
Draft Allowance
Camber Allowance
Comber Allowance / Shaking Allowance
Properties of Moulding Sand
1. Porosity
2. Flowability
3. Collapsibility
4. Adhesiveness
5. Cohesiveness
6. Refractoriness
Classification of Moulding Sand
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Green sand
Dry sand
Loom sand
Facing sand
Baking sand
System sand
Parting sand
Core sand
Oil sand
Molasses sand
Methods Used in Making The Mould
1.
2.
3.
4.
5.
6.
Pit moulding
Floor moulding
Bench moulding
Machine moulding
Plate moulding
Sweep moulding
The hole process of producing casting may be classified into Five stages
1.
2.
3.
4.
5.
Pattern making
Moulding and Casting
Melting and Casting
Fitting of the casting
Testing and inspecting
Visual Inspection
1.
2.
3.
4.
5.
Surface finishing
Casting thickness
Pressure test of casting
X- ray machine
Weight or Displacement testing
Loom Moulding process – Loam is a special strong and mixture often
containing a proportion of refactory fire clay. Which is used of moulding
heavy iron casting. The ingradients are milled in a heavy edge rammer mill
with sufficient water to form a mud. This is applied as a plaster or surface
layer to the rough structure of the mould which may be built of soft fire
bricks or dried 10 mm bricks. The wet 10mm must be sufficiently adhesive
to hold on to vertical surfaces without or pilling.
Precaution:1. First of all, we dig a pit of appropriate size with trowel.
2. We loose the sand and leveled the sand bed.
3. We pressed sand bed with help of wooden plank and smoothened it with
smoother.
Job No.-1
Object:- To make a Mould as given in the sketch below.
Material Used :- Green Sand, Dry Sand, Silica Sand, Loom Sand, Parting Sand,
Bentonite Clay, Cola Power and Graphite
Tools and Equipment Used :1) Moulding Box
2) Cleaner
3) Trowels
4) Solid Pattern
5) Pin Rammer
6) Round Rammer
7) Riddle
8) Runner Sprue
9) Moulding plate
10) Swab
11) Spad
12) Wooden Smoother
Theory :- What is Moulding Shop and it uses.
Procedure :- Write point wise.
Results:-